U.S. patent number 6,142,996 [Application Number 09/350,829] was granted by the patent office on 2000-11-07 for methods useable for forming small openings in the lens capsules of mammalian eyes.
This patent grant is currently assigned to Optex Ophthalmologics, Inc.. Invention is credited to Soheila Mirhashemi, Michael Mittelstein, John T. Sorensen.
United States Patent |
6,142,996 |
Mirhashemi , et al. |
November 7, 2000 |
Methods useable for forming small openings in the lens capsules of
mammalian eyes
Abstract
A device and system for creating small (e.g., less than 3 mm and
preferably about 1 mm in cross dimension) openings in the anterior
lens capsule of a mammalian eye to facilitate insertion of lens
reduction/removal device(s) and/or cannulae for injecting flowable
lens replacement materials into the lens capsule. The device
generally comprises a handpiece having an electrosurgical probe
extending forwardly therefrom. The electrosurgical probe
incorporates an annular tip electrode which is positionable in
contact with the lens capsule, to create the desired less than 3 mm
opening therein. The annular electrode tip may be either monopolar
or bipolar in design.
Inventors: |
Mirhashemi; Soheila (Laguna
Niguel, CA), Mittelstein; Michael (Laguna Niguel, CA),
Sorensen; John T. (Costa Mesa, CA) |
Assignee: |
Optex Ophthalmologics, Inc.
(San Juan Capistrano, CA)
|
Family
ID: |
24992589 |
Appl.
No.: |
09/350,829 |
Filed: |
July 9, 1999 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
744404 |
Nov 7, 1996 |
5957921 |
|
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Current U.S.
Class: |
606/41; 604/22;
606/107; 606/180; 606/45 |
Current CPC
Class: |
A61B
18/1402 (20130101); A61B 18/14 (20130101); A61F
9/0079 (20130101) |
Current International
Class: |
A61B
18/14 (20060101); A61B 017/36 () |
Field of
Search: |
;606/4-6,107,35,41,45,46,48,50,171,179,180 ;604/22 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Dvorak; Linda C. M.
Assistant Examiner: Ruddy; David M.
Attorney, Agent or Firm: Buyan; Robert D. Stout, Uxa, Buyan
& Mullins, LLP
Parent Case Text
This is a division of U.S. patent application Ser. No. 08/744,404
which was filed on Nov. 7, 1996 now U.S. Pat. No. 5,957,921.
Claims
What is claimed is:
1. A method for removing a lens from a mammalian eye through a
small capsulotomy opening formed in the lens capsule of the
mammalian eye leaving the central region of the anterior aspect of
the lens capsule un-incised and intact, said method comprising the
steps of:
A) providing a monopolar electrosurgical capsulotomy probe device
which has an annular electrode tip;
B) electrically coupling a secondary electrode to the body of the
patient;
C) inserting the capsulotomy device into the eye such that the
electrode tip is in contact with the lens capsule at a location
which is lateral to the central region of the anterior aspect of
the lens capsule;
D) passing electrical current through the probe and to the
electrode tip, said electrical current being of sufficient
magnitude to form a capsulotomy opening at said location while
allowing the central region of the anterior aspect of the lens
capsule to remain in tact;
E) removing the capsulotomy device from the eye;
F) providing a lens reduction device which comprises an elongate
probe having a rotating lens reducing head;
G) inserting the lens reduction device through the capsulotomy
opening created in Step D such that the rotating lens reducing head
becomes positioned within the lens capsule;
H) causing the lens reducing head to rotate so as to effect
endocapsular reduction of the lens; and,
(I) removing the reduced matter of the lens from the lens capsule
through the capsulotomy opening created in Step D.
2. The method of claim 1 wherein the electrical coupling said
secondary electrode to the body of the patient comprises attaching
said secondary electrode to the body of the patient, in abutting
contact therewith.
3. The method of claim 1 wherein the electrical coupling said
secondary electrode to the body of the patient comprises
positioning said secondary electrode in close but not abutting
proximity to the body of the patient to establish capacitive
coupling between the body of the patient and said secondary
electrode.
4. The method of claim 1 wherein Step D further comprises:
passing an electrical current having a power of approximately 10
watts, through the probe and to the electrode tip.
5. The method of claim 1 wherein the electrical current which is
passed through the probe in Step D of the method comprises pulsed
electrical current.
6. The method of claim 1 wherein the electrical current passed
through the probe in Step D the method comprises bunches of pulses
of electrical current separated by intervening period of at least
minimal electrical current.
7. The method of claim 1 wherein the electrical current passed
through the probe in Step D the method is super pulsed electrical
current.
8. The method of claim 1 wherein Step D further comprises:
passing electrical current of a generally sinusoidal weave from
through the probe and to the electrode tip.
9. The method of claim 1 wherein the capsulotomy opening created in
Step D is less than 3 millimeters in cross-dimension.
Description
FIELD OF THE INVENTION
The present invention relates generally to medical devices, and
more particularly to an electrical surgical device which is usable
to form relatively small (e.g., 1-2 mm) openings in the lens
capsule of the eye.
BACKGROUND OF THE INVENTION
Cataracts have become one of the most common causes of visual
impairment and blindness in our ageing population. Surgery is
currently the only method of restoring vision to patients who have
become visually impaired or blinded by cataracts.
Traditional cataract removal surgery requires the intact
cataract-affected lens to be removed through a 7-10 mm incision
formed in the anterior aspect of the lens capsule of the eye. After
the in-tact cataract affected lens has been removed through the
7-10 mm incision, a prosthetic lens (e.g., a transparent lens
formed of a biocompatable polymer) is then inserted through such
7-10 mm incision and implanted within the lens capsule to serve as
a replacement for the previously-removed cataract-affected lens.
These classic cataract removal procedures have proven to be
successful in restoring vision, but often are associated with
post-operative complications due to the large 7-10 mm incision
formed in the lens capsule.
More recently, another surgical procedure, known as
phacoemulsification, has been developed for removing
cataract-affect lenses. In these phacoemulsification procedures, an
ultrasonically vibrating probe is inserted into the lens capsule
through an incision formed therein. The ultrasonically vibrating
emulsification probe is then manipulated about to effect complete
emulsification of the cataract-affected lens. The emulsified lens
matter is then aspirated out of the lens capsule. Thereafter, the
desired prosthetic lens replacement is inserted into the lens
capsule. Although the diameter of the phacoemulsification probe may
be relatively small, it is still typically necessary to utilize a
capsular incision of 2.5-6.0 mm in length to allow the probe to be
manipulated about sufficiently to accomplish complete
emulsification and removal of the lens matter. Furthermore, it is
often necessary to further enlarge the capsular incision through
which the phacoemulsification probe was inserted to the usual 7-10
mm size to permit subsequent insertion of a preformed prosthetic
lens implant into the lens capsule.
The need to form a relatively large incision in the anterior lens
capsule to permit passage of a prosthetic lens replacement into the
lens capsule may soon be obviated due to certain developments in
the lens removal/replacement technology. For example, certain
injectable lens replacement materials, known in the art and/or
presently being developed, may be passed into the interior of the
lens capsule through a needle or tubular cannula. Because these
injectable lens replacement materials may be passed into the lens
capsule through a relatively small opening, the advent of these
injectable lens replacement materials may eliminate any need for
the formation of large incisions in the lens capsule to allow a
prosthetic lens to be inserted into the lens capsule.
Also, certain rotatable lens removing devices, such as those
described in U.S. Pat. No. 5,437,678 (Sorensen) as well as in U.S.
patent applications Ser. Nos. 08/421,421, and 08/658,846 may be
inserted into the lens capsule through small (e.g., less than 3 mm)
openings and may be held substantially stationary during lens
reduction and removal, thereby avoiding any need for forming any
large (e.g., greater than 3 mm) capsular incision.
In view of the development of modern injectable lens replacement
materials and rotatable lens removing devices which may be inserted
and operated through relatively small openings in the lens capsule,
it is now possible to perform an entire cataract removal and
prosthetic lens replacement, through a small (e.g., less than 3 mm)
opening in the anterior lens capsule, while allowing the remainder
of the anterior lens capsule to remain in-tact and unincised.
However, the process of creating a small (e.g., less than 3 mm)
opening in the anterior lens capsule is problematic due to the
tendency of the lens capsule material to tear or "run" when
punctured.
Accordingly, there presently exists a need for a new device capable
of consistently making small (e.g., less than 3 mm) openings in the
anterior lens capsule of the eye.
SUMMARY OF THE INVENTION
The present invention provides electrosurgical devices and methods
for forming small (e.g., less than 3 mm) openings in the anterior
lens capsule of the mammalian eye.
In accordance with the invention, there is provided an
electrosurgical probe device generally comprising: a) an elongate
probe which has a proximal end, a distal end and a longitudinal
axis projectable therethrough, and, b) an annular electrode tip
located on the distal end of said elongate probe, said annular
electrode tip having a lens capsule contacting surface which lies
substantially in, or is substantially disposable in, a plane that
is nonparallel to the longitudinal axis of the probe, said probe
being thereby insertable into the eye such that the lens capsule
contacting surface of the annular electrode tip is in contact with
the lens capsule, whereby passage of electrical current through
annular electrode tip will create an opening in the lens
capsule.
Further in accordance with the invention, the above-summarized
probe device may be of a monopolar or bipolar type. If the device
is of a monopolar type, a second electrode (e.g., a plate
electrode) will necessarily be attached to, or placed in sufficient
proximity to be electrically coupled to, the body of the patient to
complete an electrical circuit or between the electrode tip of the
device and the second electrode. On the other hand, if the device
is of the bipolar type, the second electrode will be formed or
mounted upon the body of the probe, and no externally-attached
second electrode will be required.
Still further in accordance with the invention, there is provided
an electrosurgical system for forming small (e.g., less than 3 mm)
openings in the anterior lens capsule of the mammalian eye, said
system comprising an electrosurgical probe device of the
above-described character, further in combination with: a handpiece
sized and configured to be grasped by the human hand, said
handpiece having a distal end and a proximal end; an electrical
signal generating apparatus which is connectable to said handpiece;
an on/off switch for starting and stopping a flow of current from
the electrical signal generating apparatus to the handpiece;
connector apparatus to connect the distal end of the handpiece to
the proximal end of said probe device and to pass said electrical
current from the hand piece to the annular electrode tip of the
probe.
Still further in accordance with the invention, there is provided a
method for forming an opening in the lens capsule of the eye, said
method generally comprising the steps of: a) providing an
electrosurgical probe device comprising an elongate probe having a
proximal end, a distal end, and an electrode tip formed on the
distal end thereof; b) inserting the probe into the eye such that
the electrode tip is in contact with the lens capsule of the eye;
c) passing electrical current through the probe and to the
electrode tip, said electrical current being of sufficient
magnitude to form an opening in said lens capsule at the location
where said electrode tip is in contact with the lens capsule.
Further objects and advantages of the present invention will become
apparent to those skilled in the art upon reading and understanding
of the following detailed description and the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view showing an electrosurgical probe
device of the present invention operatively inserted into a human
eye.
FIG. 1a is an enlarged perspective view of the distal portion of
the electro-surgical probe device of FIG. 1.
FIG. 2 is a perspective view of a system of the present invention
comprising a) an electrical signal generating apparatus, b) a
handpiece, and c) an electrosurgical probe device of the present
invention mounted on the distal end of the handpiece.
FIG. 2A is a partial perspective view of a connector assembly,
formed on the distal end of the handpiece shown in FIG. 2.
FIG. 3 is a rear perspective view of a monopolar embodiment of the
electrosurgical probe device of the present invention.
FIG. 4 is a longitudinal sectional view of the monopolar
electrosurgical probe device shown in FIG. 3.
FIG. 4A is a partial longitudinal sectional view of the distal end
of the monopolar electrosurgical probe of FIG. 4.
FIG. 5 is a perspective view of a segment of hypotubing from which
a notch has been removed to form an annular electrode tip usable in
the electrosurgical probe devices of the present invention.
FIG. 5a is a perspective view of an annular electrode tip formed
from the notched segment of hypotubing shown in FIG. 5.
FIG. 6 is a perspective cut-away view of the monopolar embodiment
shown in FIGS. 3-4.
FIG. 7 is a perspective cut-away view of a first bipolar embodiment
of an electrosurgical probe device of the present invention.
FIG. 8 is a cross sectional view through line 8--8 of FIG. 7.
FIG. 9 is a longitudinal sectional view of a second (alternative)
bipolar embodiment of an electrosurgical probe device of the
present invention.
FIG. 10 is a cross sectional view through line 10--10 of FIG.
9.
FIGS. 11a-11c are graphic representations of power vs. time,
illustrating variation in the electrical wave forms and power
levels which may be utilized in conjunction with the device and
system of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following detailed description and the accompanying drawings
are provided for the purpose of illustrating and describing
presently preferred embodiments of the invention only, and are not
intended to limit the scope of the invention in any way.
With reference to the drawings, there is provided an
electrosurgical probe device 10 which is usable to form small
openings (e.g., less than 3 mm) in the anterior lens capsule LC of
the eye. In general, the electrosurgical probe device 10 comprises
a proximal attachment/contact hub 12 having an elongate probe
member 14 extending distally therefrom, and an annular electrode
tip 16 mounted on the distal end of the elongate probe portion 14.
The annular electrode tip 16 is disposed at an angle relative to
the longitudinal axis LA of the elongate probe portion 14.
FIG. 1 shows a preferred method by which the electrosurgical probe
device 10 of the present invention may be inserted into the eye E
for the purpose of forming a small (e.g., less than 3 mm) opening
in the anterior lens capsule LC of the eye E. It will be noted from
FIG. 1 that the lens capsule LC is suspended within the eye E,
behind the anterior chamber AC and cornea C. The lens capsule LC is
maintained in its normal anatomical location by various anchoring
structures of the eye, including suspensory ligaments SL which are
located posterior to the iris I of the eye E. A round central
region CR is definable at the center if the anterior aspect of the
lens capsule in direct alignment with the center of the
variably-sized opening of the iris I. In operation, a small
incision is formed in the cornea C and the elongate probe portion
14 of the device 10 is inserted through such incision, and is
advanced through the anterior chamber AC of the eye E until the
annular electrode tip 16 comes into contact with the anterior
aspect of lens capsule LC, at a location outside of the central
region CR, as shown. Thereafter, electrical current is passed
through the annular electrode tip 16 so as to cause the tip 14 to
penetrate the lens capsule LC, thereby forming an annular opening
which is approximately of the same size and configuration as the
annular electrode tip 16.
As the annular electrode tip 16 electrosurgically penetrates the
lens capsule LC, heat will cauterize or melt the portion of the
lens capsule LC which surrounds the opening formed by the electrode
tip 16, thereby strengthening or reinforcing the edges of such
opening. Such strengthening or reinforcement of the periphery of
the opening will prevent or deter subsequent tearing, undesired
enlargement or extension of the opening as the cataract removal
and/or lens replacement instruments are passed through the
opening.
With reference to FIG. 2-2a, the electrosurgical probe device 10 of
the present invention may be constructed and configured so as to be
usable as an attachment to an electrocautery system of a type
typically used in ophthalmological surgery. Such electrocautery
systems typically comprise a handpiece 18, an electrical signal
generator 20 and an on/off switch such as a foot pedal 22.
One example of a commercially available electrocautery system of
the type shown in FIGS. 2-2a is the Surgitron.TM. Model FFPF
available from Ellman International, Inc., 1135 Railroad Avenue,
Hewlett, N.Y. 11557.
In the embodiment shown in FIGS. 2-2a, a connector assembly 24 is
formed on the distal end of the handpiece 18 to facilitate
connection with an electrical contact to the electrosurgical probe
device 10 of the present invention. In the embodiment shown, the
connector assembly 24 comprises a generally cylindrical, distally
extending contact post 26 surrounded by an internally threaded,
rotatable, Luer-lock sleeve 24. The contact post is insertable into
a receiving contact bore formed on the proximal end of the probe
device 10, and the Luer-lock sleeve is then usable to engage and
lock the probe device 10 to the handpiece 18 such that the contact
post 26 of handpiece 18 is held in firm electrical contact with the
probe device 10.
It will be appreciated that the electrosurgical probe device 10
generally described hereabove, may be specifically constructed in
either monopolar or bipolar embodiments, as more fully described
herebelow:
i. Monopolar Embodiments
FIGS. 3-6 show a monopolar electrosurgical probe device 10a of the
present invention, which is usable in conjunction with an
electrocautery system of the type shown in FIGS. 2-2a.
As shown in FIGS. 3-6, the monopolar electrosurgical probe device
10a is constructed such that the annular electrode tip 16a is the
only electrode present on the body of the probe device 10a. A
second electrode, such as a plate electrode (not shown), must be
separately attached to or brought into proximity with the body of
the patient in order that an electrical circuit or capacitive
coupling be completed between the annular electrode tip 16a and
such externally-placed second electrode (not shown).
As shown, the proximal hub 12a of the monopolar probe device 10a
comprises an electrically conductive, generally cylindrical, hub 30
having a Leur-lock flange 32 formed therearound. An insulative
covering 34, formed of polyvinyl chloride (PVC) or other suitable
plastic, may be formed about the outer surface of the cylindrical
hub 30, but should not interfere with the engagement of the
Luer-lock flange 32 to the internal threads of the rotatable sleeve
28 of the handpiece connector assembly 24.
The distally-extending probe portion 14a of the monopolar probe
device 10a may comprise a rigid base tube 36 which is continuous
with and protrudes distally from the frusto-conical proximal hub 30
as shown. A first hypotube member 38 is inserted into a distal
portion of the base tube 36, and extends axially therefrom, as
shown. A second hypotube member 40 is inserted into a distal
portion of the first hypotube member 38, and extends distally
therefrom, as shown. The annular electrode tip 16a is formed on the
distal end of this second hypotube member 40.
One means by which the annular electrode tip may be formed on the
distal end of the second hypotube member 40 is illustrated in FIGS.
5 and 5a. With reference to FIGS. 5-5a the second hypotube member
40 has a notch 42 cut away therefrom. Such notch 42 is configured
such that its distal edge is perpendicular to the longitudinal axis
LA of the second hypotube member 40, and its proximal edge is
curved or acutely angled relative to such longitudinal axis LA.
This results in the formation of a substantially cylindrical ring
at the distal end of the second hypotube member 40, such ring being
connected by a remnant portion 44 of the second hypotube 40 to that
proximal portion of the second hypotube 40 located proximal to the
notch 42.
The distal surface DS of the cylindrical ring formed at the distal
end of the second hypotube member 40 is initially disposed in a
plane which is perpendicular to the longitudinal axis LA. However,
the remnant portion 44 is bent in a direction away from the
longitudinal axis LA such that the plane P of the distal surface of
the ring member at the distal end of the second hypotube member 40
forms an internal angel A relative to the longitudinal axis LA.
Also, electrically conductive wire 54 is soldered or otherwise
affixed to the interior of the second hypotube member 40.
Upon assembly, the proximal portion of the second hypotube member
prepared as shown in FIG. 5a, is inserted into the distal portion
of the bore of the first hypotube member 38, and is affixed
thereto. Similarly, the first hypotube member 38 is affixed to the
base tube 36 which in turn is affixed to the frusto-conical
proximal hub 30. Such direct affixation of the hypotube member 38,
base tube 36 and frusto-conical proximal hub 30 may be sufficient
to provide reliable electrical contact and conduction therebetween.
However, if reliable electrical contact and conduction between such
components is not accomplished by their direct affixation to one
another, an added electrical conductive wire 54 may optionally be
soldered or otherwise electrically connected to any or all of the
hypotube member 38, base tube 36 and/or proximal hub 30, to
facilitate electrical conduction therebetween.
The angle A of the distal surface DS of the annular electrode tip
16a of the probe device 10a may vary, depending on the intended
positioning of the electrosurgical probe device 10a within the eye
E. Typically, it will be desirable to position the electrosurgical
probe device 10a in a manner similar to that shown in FIG. 1. Thus,
in most cases, it will be desirable for the distal surface DS of
the annular electrode tip 16a to form an internal angle A of no
less than 90.degree. and typically in the range of
90.degree.-150.degree.. In the embodiment shown, a first insulative
sheath 50 is heat-shrunk or otherwise secured about the proximal
portion of the second hypotube member 40 and the distal portion of
the first hypotube member 38. This insulative sheath 50 helps to
securely join the first 38 and second 40 hypotube members together
and also provides an insulative outer covering thereon. A second
insulative sheath 52 is then formed about the proximal portion of
the first insulative sheath 50 and about the base tube 36.
The monopolar electrosurgical probe 10a is attachable to the
connector assembly 24 of the electrocautery system shown in FIGS.
2-2a by inserting the contact post 26 of the connector assembly 24
into the proximal hub 30a such that the outer surface of the
contact post 26 is in direct abutting contact with the inner
surface of the frusto-conical hub 30a. Thereafter, the rotatable
sleeve 24 is rotatably advanced such that the internal threads of
the rotatable sleeve 34 will engage the Luer-lock flange 32a of the
proximal hub 30. In this manner, electrical current from the
electrical signal generator 20 will pass through the hand piece 18,
from the contact post 26 and to the hub 30a of the probe device
10a. Such current will then pass from the hub 30 through the
electrically conductive walls of the first 38 and second 40
hypotube members and/or through the electrically conductive wire
54. The current will then pass from the annular electrode tip 16a
to a second electrode (not shown) which has been attached to or
brought into proximity with the patient's body to complete the
electrical circuit or establish the required capacitive
coupling.
ii. Bipolar Embodiments
FIG. 7-8 show a first embodiment of a bipolar electrosurgical probe
10b of the present invention, while FIGS. 9-10 show an alternative
bipolar electrosurgical probe 10c which has a structure
substantially similar to (and which shares many common structural
attributes with) that of the monopolar embodiment 10a described
hereabove and shown in FIGS. 3-6.
With reference to FIG. 7-8, this bipolar probe device 10b of the
present invention comprises an elongate probe portion 14b formed of
an inner tubular electrode member 60, an outer tubular electrode
member 62 and an insulating tubular sheath 64 positioned
therebetween. The inner tubular electrode 60 member, outer tubular
electrode member 62 and insulative tubular sheath 64 are disposed
coaxially about a common longitudinal axis LA. The distal end of
the inner tubular electrode 60 forms the annular electrode tip 16b.
In the embodiment shown, this annular electrode tip 16b is formed
by cutting the distal end of the inner tubular electrode 60 such
that the it's distal surface is perpendicular (i.e., at a
90.degree. angle) relative to the longitudinal axis LA. It will be
appreciated, however, that the distal end of the inner tubular
electrode 60, the outer tubular electrode 62 and/or the interposed
sheath 64, may be cut at various angles relative to the
longitudinal axis LA, so as to provide different angular
dispositions of the annular electrode tip 16b. Similarly, the
distal end of the outer electrode member 62 as well as the
insulation sheath 64 may be axially spaced and fastened to one
another such that the respective distal ends of the inner tubular
electrode 60, insulation sheath 64 and outer electrode members 62
will form such angle.
The elongate probe portion 15b of this first bipolar probe 10b
shown in FIG. 7-8 extends distally from and is connected to a
proximal hub (not shown) which may be substantially the same as the
proximal hub 12a described hereabove with respect to the monopolar
probe device 10a. However, in this bipolar embodiment, only the
inner tubular electrode 60 is electrically connected to the
proximal hub, and the outer tubular electrode 62 is connected
separately by a separate electrical connection to the signal
generating apparatus 20, thereby completing the desired bipolar
circuit of this embodiment.
As shown in FIG. 7, the distal end of the outer tubular electrode
62 may terminate a spaced distance proximal to the distal end of
the inner tubular electrode 60. Also, the distal portion of the
tubular insulating sheath 64 which protrudes beyond the distal end
of the outer tubular electrode may be tapered, in the manner shown
in FIG. 7. In this manner, when the bipolar probe device 10b is
inserted into the eye, the distal end of the inner tubular
electrode 60 is positioned in contact with the lens capsule LC.
Thereafter, when energized, electrical current will flow between
the distal end of the inner tubular electrode 60 (which forms the
annular electrode tip 16b) the adjacent distal portion of the outer
tubular electrode 62. Thus, in this first bipolar embodiment, there
is no need for a separate external electrode to be attached to or
brought into proximity with the patient's body, as is required of
the above-described monolar polar probe device 10a.
FIGS. 9 and 10 shows an alternative or second embodiment of a
bipolar probe device 10c which is similar in construction to the
monopolar probe 10a described hereabove. This second embodiment of
the bipolar probe 10c comprises a proximal hub 12c having an
elongate probe portion 14c extending axially therefrom, in a distal
direction. An annular electrode tip 16c is formed on the distal end
of the probe portion 14c. The cylindrical hub 30c, first hypotube
member 38c, second hypotube member 40c, remnant portion 44c,
annular electrode 16c and electrically conductive wire 54c are
constructed, configured and assembled in the same manner as
described hereabove with respect to the monopolar embodiment.
However, in this second bipolar embodiment, an outer electrode tube
70, formed of electrically conductive material, surrounds the
insulative sheet 50c. Such outer electrode tube 70 is connected to
an electrically conductive wire 55 which extends through the
insulative casing 34c of the proximal hub 12c and is connectable to
the electrical signal generating device 20. The outer electrode
tube 70 is distally coterminous with the insulative sheath 50c,
such that only the remnant portion 44c of the second hypotube
member 40c and the annular electrode tip 16c protrude distally
beyond the distal end of the outer electrotube 70.
In operation, this second bipolar embodiment of the device 10c is
inserted into the eye such that a distal portion of the probe
portion 14c extends through the anterior chamber AC, and the distal
surface DS of the annular electrode tip 16c is in contact with the
anterior lens capsule. Thereafter, electrical current from the
electrical signal generator 20 may pass through the electrically
conductive wire members 54c, 55 and/or other electrically
conductive portions of the probe device 10c as described hereabove,
such that current will flow from the annular electrode tip 16c to
the distal portion of the outer tubular electrode 70 through the
electrically-conductive fluid environment within the anterior
chamber of the eye.
It will be appreciated that the annular electrode tip 16, 16a, 16b,
16c described hereabove may comprise any appropriate geometrical
configuration, and may have an open center (e.g., a ring or hoop)
or alternatively may have a solid center (e.g., a disc having a
generally annular outer edge). Furthermore, it will be appreciated
that the lens capsule contacting surface, such as the distal
surface, of the annular electrode tip 16, 16a, 16b, 16c need not be
substantially flat or planar, and may be slightly concave or of any
other suitable configuration. In this manner, when reference is
made in this patent application to the "plane" in which the lens
capsule contacting surface of the distal electrode tip lie, it will
be appreciated that such plane may be projected through a concaved
or wavy surface of an average variant thereof. Alternatively, in
embodiments wherein the lens capsule contacting surface of the
annular electrode tip 16, 16a, 16b, 16c is flat, such entire flat
edge may lie within the referenced plane.
iii. Preferred Methods of Operating the Devices
Any and all of the above-described embodiments of the present
invention are preferably operated in accordance with a general
method wherein at least a distal portion of the elongate probe
portion 14, 14a, 14b, 14c is inserted through an incision in the
cornea C and is advanced through the anterior chamber AC until the
lens-capsule-contacting distal surface DS of the annular electrode
tip 16, 16a, 16b, 16c is in contact with the lens capsule LC. If a
monopolar embodiment of the probe device 10a is used a secondary
electrode will be attached to or brought into close proximity with
the body of the patient at a location which is suitable to complete
an electrical circuit between the annular electrode tip 16a of the
probe 10a and such second electrode. On the other hand, if one of
the bipolar embodiments of the probe device 10b, 10c are used,
there will be no need to provide a separate second electrode with
is attached to or placed in proximity with, the body of the
patient.
Thereafter, the electrical signal generating device 20 is actuated
so as to cause current to flow between the annular electrode tip
16, 16a, 16b, 16c and either the separately attached secondary
electrode (monopolar embodiment) or the on-board outer electrode
tube 62, 70.
Any suitable electrical wave form and power level may be used. In
this regard, in at least some applications it will be desirable to
use a continuous, pulsed or superpulsed wave form which provides an
average power level of approximately 10 watts to form the desired
opening in the anterior lens capsule.
In embodiments of the system wherein the wave form is intended to
be pulsed or superpulsed, the signal-generating device 20 will
preferably include a mechanism for setting the desired pulse
duration, pulse train duration, pulse bunch duration and/or duty
cycle, examples of which are shown graphically in FIGS. 11a, 11b
and 11c.
With reference to 11a, there is shown the average power generated
by single pulse, of known pulse duration PD.
FIG. 11b shows the average power generated by a train of individual
pulses, each of said individual pulses having a pulse duration PD,
and the overall train of pulses having a pulse train duration
PTD.
FIG. 11c shows a superpulsed embodiment of the invention wherein
bunches of small individual pulses, each of said individual pulses
having a pulse duration PD of 10 milliseconds, are generated
periodically on a given repeat period RP.
It will be appreciated that the electrical signal generating device
20 may be preprogrammed to deliver desired energy levels, and/or
wave form(s) in response to each triggering of a fixed on-off
switch. Alternatively, the signal generating device 20 may be
rheostatically controlled by way of a foot pedal or other type of
rheostatic control device, and the amount and duration of energy
delivered through the annular electrode tip 16, 16a, 16b, 16c will
be determined by the current position of the foot pedal or other
rheostatic control mechanism.
In the above-described manner, the electrosurgical probe device 10
of the present invention is usable to form an opening in the lens
capsule LC of a size which is only slightly larger than the outer
diameter of the annular electrode tip 16, 16a, 16b, 16c.
Furthermore, when the preferred wave form and power setting are
used, the resultant electrosurgical opening of the lens capsule
will additionally form a heat-fused region around such opening,
thereby preventing the anterior aspect of the lens capsule from
being torn, enlarged or extended during the subsequent insertion
and manipulation of the cataract removal device(s) and/or
prosthetic lens implant introduction cannula.
The present invention has been described hereabove with reference
to certain presently preferred embodiments only. No attempt has
been made to exhaustively describe all possible embodiments in
which the invention may be practiced. Indeed, various additions,
deletions, modifications and alterations may be made to the
above-described preferred embodiments without departing from the
intended spirit and scope of the invention. Accordingly, it is
intended that all such reasonable additions, deletions,
modifications and alterations be included within the scope of the
following claims.
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